Scientists prepare natural enemy to fight one of Australia's worst weeds

Queensland's Ecosciences Precinct has strict standards. (Supplied: Jason Callander Biosecurity Queensland) A blister rust plant pathogen that will spread on the wind is being readied for release against one of Australia's worst weeds. Scientists say the fungus is a natural enemy of lantana and was tested to ensure it will not seriously harm other plants. The pathogen will be bred and distributed to Landcare groups and local councils. Link copiedShareShare articleUnder quarantine lockdown in Brisbane's Ecosciences Precinct, an imported plant pathogen is being readied for release, its microscopic spores to be spread by the wind. Puccinia lantanae leaf blister rust is being incubated in a laboratory with strict biosecurity measures. Scientists shower on exiting. (Supplied: Jason Callander Biosecurity Queensland) Scientists working with it change clothes on entry and shower in a stainless-steel decontamination room before leaving the lab. The fungal biocontrol they have been nurturing is one last approval away from being deployed against one of Australia's worst noxious weeds. The lantana rust weakens the weed, damaging its leaves. (Supplied: Jason Callander Biosecurity Queensland) A poisonous, pretty, prolifically flowering shrub, Lantana camara was introduced from the Americas in the 1840s. But it escaped from gardens and has since invaded about 5 million hectares of pasture, bush and rainforest across New South Wales, Queensland, Victoria, Western Australia and the Northern Territory. Banned from sale, the drought and heat-tolerant plant forms thickets that smother native habitat, kill livestock naive to its toxicity, and add dangerous fuel to bushfires. Hardy and pretty, lantana was introduced to Australia as a garden plant. (ABC Rural: Jennifer Nichols) A report by the National Lantana Group in 2007 estimated that lantana cost the grazing industry alone more than $100 million annually in lost productivity. Weeds Australia warns that all parts of the hardy plant are poisonous to humans if eaten, causing vomiting, diarrhoea, muscle weakness, breathing problems, and sometimes, death. Gloves are recommended to avoid touching it. Weeds Australia has a lantana camara distribution map. (Supplied: Weeds Australia) In addition to herbicides and manual removal, more than 30 biological controls for lantana have been imported and released since 1914, 17 of which have become established. But birds quickly spread lantana seeds, and bug biocontrols, sensitive to seasonal conditions, have not kept up with the weed's relentless march. In April, federal authorities recommended approving the Queensland Department of Primary Industries's (DPI) application to release a South American blister-leaf rust against Lantana camara. Jason Callander is overseeing the lantana rust program. (Supplied: Jason Callander Biosecurity Queensland) DPI scientist Jason Callander said the Puccinia lantanae fungus infects lantana's leaves, shoot tips, and stems, resulting in dead tissue spots (cankers) and stem dieback. The scientists have submitted a "release from quarantine protocol" request to the federal government's plant imports operations team, the final approval required to start the program. They will spend the next year breeding up the rust to give to Landcare groups and local councils to help propagate and spread it. Lantana quickly displaces plants, forming dense thickets. (ABC Rural: Jennifer Nichols) The leaf blister rust pathogen was tested on 55 non-target plants most likely to be affected at the UK's Centre for Agriculture and Biosciences International. A 37-page risk analysis found it was "host-specific" to Lantana camara, and the risk to other species was "negligible". While two native verbenas, V. africana and V. gaudichaudii, may suffer symptoms, it was "not anticipated" to cause "plant mortality". "Both of these plants grow in central western Queensland, outside of the range that we expect the rust to be able to persist," Mr Callander said. Birds and livestock can spread the seed in their manure. (ABC Rural: Jennifer Nichols) Adding urgency to the need for a solution is lantana's toxicity; it can kill cattle, sheep, goats, guinea pigs and rabbits. Joanne Connolly is a mobile cattle vet and hobby farmer at Nebo, about 100 kilometres south-west of Mackay in North Queensland. Joanne Connolly has experienced lantana poisoning of her own stock. (Supplied: Joanne Connolly) When one of her steers ran to find shade, with mucous streaming from its nose, she suspected lantana poisoning. "If it's bad enough, it can cause death," Dr Connolly said. A runny nose is one of the symptoms. (Supplied: Joanne Connolly) The steer survived, but Dr Connolly said the weed's toxins damage the liver, causing extreme sensitivity to the sun, lethargy, and yellowing around the eyes. "It can be quite dramatic; the skin can literally just start to lift off," she said. Hungry cattle, newly introduced to lantana plants a

Scientists prepare natural enemy to fight one of Australia's worst weeds

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Scientists prepare natural enemy to fight one of Australia's worst weeds

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